1. Field of the Invention
The present invention relates generally to a suspension of a vehicle such as an automobile, and more particularly, to an independent steering suspension for a steering vehicle wheel.
2. Description of the Prior Art
As an independent steering suspension for a steering vehicle wheel, there has been proposed in Japanese Patent Laid-open Publication 6-211014 such a construction that a carrier for supporting the steering vehicle wheel to be rotatable about its rotation axis is supported by a knuckle to be angularly movable about a steering axis extending substantially vertically, and the knuckle is supported by an upper arm assembly and a lower arm from the vehicle body, wherein the upper arm assembly is mounted between an upper portion of the knuckle and an opposing portion of the vehicle body to include a first vertical arm member closer to the knuckle and a second horizontal arm member closer to the vehicle body and extending substantially in the lateral orientation of the vehicle body, while the lower arm is mounted between a lower portion of the knuckle and an opposing portion of the vehicle body to extend substantially in the lateral orientation of the vehicle body, the upper arm second member having a general plan configuration of the alphabetic letter A to have a broad end corresponding to the bottom of A and a narrow end corresponding to the top of A, the lower arm having a general plan configuration of the alphabetic letter Y to have a broad end corresponding to the top of Y and a narrow end corresponding to the bottom of Y, the upper arm second member being pivotably connected with the upper arm first member at the narrow end and with the opposing vehicle body portion at the broad end, the lower arm being pivotably connected with the knuckle lower portion at the broad end and with the vehicle body at the narrow end, with a strut bar being pivotably mounted between the knuckle and an opposing portion of the vehicle body to extend substantially in the longitudinal direction of the vehicle. A steering means is mounted between the carrier and the vehicle body to variably determine an angular position of the carrier about the steering axis relative to the vehicle body, and a vertical load reaction means including a spring and a damper is mounted between the knuckle and the vehicle body to extend substantially vertically.
In the above-mentioned prior art construction, when the compliance of the suspension in the longitudinal orientation of the vehicle, desired for attenuating a shock caused by the vehicle wheel running on a convex irregularity of the road surface, is increased, the caster angle will be substantially decreased when the vehicle wheel is braked, deteriorating the caster angle stability of the suspension.